The present invention relates to a system for controlling the position of a bucket supported on a boom.
Load handling equipment and vehicles, such as industrial and agricultural loaders, often include leveling systems which control the orientation of the bucket while the boom is raised or lowered. In some hydraulic bucket leveling systems, fluid may be supplied to the bucket cylinder from the boom cylinder. In other leveling systems, fluid is supplied to the bucket cylinder from a pump or other pressure source. In systems which utilize pump output flow for bucket leveling, since pump flow is diverted from the boom cylinder to the bucket cylinder, either the pump capacity must be increased or else longer cycle times endured, than in a system without bucket leveling. Systems which rely entirely on fluid from the boom cylinder may be inaccurate due to temporary absences of boom return flow or variances in return flow resulting from changing load pressures or cycle rates. Systems which derive leveling flow from slave cylinders require that the slave cylinder displacements be carefully matched to the geometry and bucket cylinder displacements of the boom/bucket system.